Eh...
Daikatana wasn't the worst FPS I ever played, definitely not the best. It was ho-hum and mediocre at best, boringly kind of generically bland. It was the Kix cereal of the FPS world honestly...
And let's be honest, there were a bunch of better FPS games out at this time. I am sure John Romero had a ton of good ideas... just they either got scrapped or were woefully implemented. Mind you, I played the PC version of it.
I can't comment on the N64 or GBC versions, as the PC version left that...You know the "I just threw up" aftertaste in my mouth.